Think about the date of that first atomic bomb test: July 16, 1945.
Some three weeks later, thanks to the success of that test, the United States took a second atomic bomb (already nearly complete), and used it to explode over the skies of Hiroshima, Japan on August 6, 1945.
Yes, this bomb exploded in the skies OVER Hiroshima - as planned. The bomb that took out Nagasaki on August 9, 1945 struck the ground, as planned.
Each bomb had a different payload... different amount of radioactive material, and even different radioactive material.
You might want to take a peek at a story I wrote about the ready-to-have-been deployed THIRD atomic bomb for Japan - see HERE.
If you look at the bottom of the film above, you can see the destructive force being pushed outwards at the 0.016 second mark of its detonation. 0.016 seconds...
You can also see with the measurement, that the base of the explosion in just 0.016 seconds is already 300 meters (~ 984 feet) wide, or thereabouts.
Anyhow... as grotesque as the aftereffects of an atomic bomb can be, the photograph is hauntingly beautiful.